In recent years, there has been an increasing interest both in the medical profession and in the general public in improved nutrition and healthy eating. As a result of this interest, there is a growing market for natural, plant-based food additives and food supplements.
Among these are plant-derived polysaccharide gums which can be used as dietary soluble fibre in functional foods and natural health products, as thickeners and stabilisers in the food industry, as moisturisers in cosmetics, as lubricants for personal use and as a basis for artificial saliva and tears for medical use.
Soluble dietary fibre components such as flax polysaccharide gum have been shown to reduce serum triglyceride and cholesterol levels and assist in management of serum glucose levels in animals. In humans, also, dietary fibre has been shown to be a vital component of a healthy diet, imparting a wide range of benefits for cardiovascular health, gastrointestinal health, immune function, weight control and cancer prevention.
Polysaccharide gums or mucilages can be obtained from a variety of plants including cereals, pseudocereals, legumes and oilseeds.
Polysaccharide gums have traditionally been extracted from plant materials with water or an aqueous solution, followed by alcohol precipitation of the gums. This process, however, also results in protein extraction and precipitation and the gum preparation produced contains a large amount of protein, which affects the physical, chemical and biological properties of the gum.
One excellent source of polysaccharide gum is flaxseed and extraction of gum from flax meal, the residue after oil extraction, is especially attractive as providing a commercial use for the meal which otherwise has had little application for human food use. Contamination of the gum with protein is, however, exacerbated when meal is used as starting material. For example, when such a process is employed on flaxseed meal, the resulting product can contain up to 60% protein (U.S. Pat. No. 5,925,401).
One approach to reducing protein contamination of gum is described in U.S. Pat. No. 2,593,528 which teaches fractionation of flaxseed into hull and kernel fractions and extraction of gum from the hull fraction alone.
Canadian Patent Application No. 2,462,538 describes the production of a “fibre-rich fraction” from oilseed meal but their initial treatment of the meal with a mixture of polysaccharidases would not yield high molecular weight polysaccharide gum. The “fibre fraction” also contained high levels of lignin.
U.S. Pat. No. 6,482,430 describes the production of a gelling hemicellulose from bran, which has a low protein content.
There remains a need for improved processes, suitable for commercial scale use, to produce high quality polysaccharide gum with minimal protein contamination.